Compositions, methods and devices for control and clean-up of hazardous spills

ABSTRACT

Disclosed are methods for treating hazardous materials, such as those which result from an unwanted spill or leak, which comprise one or more of the steps or effects of: neutralizing the dispersed material; solidifying the dispersed material; immobilizing the material; and/or reducing the evolution of harmful or unwanted gaseous forms from the spillage, preferably using a binding agent which comprises a polyacrylate-polyacrylamide cross-linked copolymer.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of, and thus claims priorityunder 35 U.S.C. §120 to, U.S. patent application Ser. No. 12/132,764,filed on Jun. 4, 2008, which claims priority under 35 U.S.C. §119(e) toU.S. Provisional Application No. 60/943,044, filed on Jun. 9, 2007, andto U.S. Provisional Application No. 60/943,447, filed on Jun. 12, 2007.U.S. patent application Ser. No. 12/132,764 and U.S. ProvisionalApplication Nos. 60/943,044 and 60/943,447 are incorporated herein byreference.

BACKGROUND

1. Field of Invention:

The present invention relates to compositions, methods, and devices forcontainment, mitigation, neutralization and/or clean-up of unwanteddispersals of hazardous material, particularly spills of acidicmaterials such as hydrogen fluoride-containing compositions.

2. Description of Related Art:

Hydrogen fluoride is a well known compound that is used in industry in avariety of processes including in alkylation reactions as a catalyst, influorination reactions as a fluorinating agent, in the manufacture offluorides, in the separation of uranium isotopes, and in the productionof fluorine containing plastics. It is well known that hydrogen fluorideis a volatile, extremely hazardous substance. Moreover, the high vaporpressure of hydrogen fluoride renders it readily aerosolizable.

Various compositions and methods have been known to be useful for theclean-up of hazardous materials, particularly acid-containing materials,and more particularly materials which contain hydrogen fluoride.However, many of these compositions and methods have certaindisadvantages.

U.S. Pat. No. 4,383,868—Braley relates to a method of treatment ofspillages of hazardous chemicals in a liquid form, and in particular toa method of treatment of such spillages for controlling and clean-up ofa spill of hydrofluoric acid. The method disclosed in this patentinvolves the application to a spill of a solid particulate mixturecontaining both polyacrylamide and a polymer or copolymer of analkyl(alk)acrylate. The material is said to immobilize the spillage andreduce the evolution of fumes from the spillage, and is said to be moreeffective in the treatment of spillages of many hazardous liquidchemicals than is either the polyacrylamide or thepolyalkyl(alk)acrylate when used alone. The U.S. Pat. No. 4,383,868patent indicates that the polymer or copolymer of the alkyl(alk)acrylatemay be a polymer derived from one or more alkyl(alk)acrylates, e.g.methyl acrylate, ethyl acrylate, methyl methacrylate, butyl methacrylateor ethyl methacrylate, or it may be a copolymer of a substantialproportion of units derived from one or more alkyl(alk)acrylates, e.g.at least 80 mole %, and units derived from one or more ethylenicallyunsaturated monomers copolymerisable therewith. The patent teaches thatthe amount of polymer or copolymer of the alkyl(alk)acrylate should notbe present in the composition in an amount that is greater than 80% byweight of the particulate mixture used in the treatment of hazardouschemicals.

U.S. Pat. No. 4,865,761—Mandel et al. relates to methods andcompositions for neutralizing and solidifying hazardous organic spills.The disclosed composition, in addition to optional ingredients, containsabout 5 to 30% of absorptive clay and about 10 to 50% portland cement.Such compositions and methods have the disadvantages of being relativelyheavy to transport to the site of the hazardous spill as well as thedifficulty associated with cleanup and/or recovery of the hazardousmaterial once it is neutralized and absorbed into the disclosedcomposition.

While prior methods may have achieved some degree of success, applicantsbelieve that several disadvantages exist and that there is a need forbetter methods, devices and compositions. For example, applicantsbelieve that a need continues to exist for clean-up and treatmentmaterials and methods in which the treating materials have advantageousproperties, such as higher capacity to absorb, retain, immobilize, etc.the hazardous material, such as HF, per unit mass of treatment material.The present invention satisfies these needs among others.

SUMMARY OF THE INVENTION

This invention is directed to novel compositions and methods, and todevices which use such compositions and methods, to treat hazardousspill conditions. As used herein, the term “treat” means to lessen orreduce the negative or harmful effects on the environment and/or livingthings of a dispersal of chemicals, usually in the form of an unintendedspill of such materials. In certain preferred embodiments, the hazardousmaterial comprises an acid-containing material. The treatment methods ofthe present invention in preferred embodiments may comprise one or moreof the steps or effects of: neutralizing the dispersed material;solidifying the dispersed material; immobilizing the material; and/orreducing the evolution of harmful or unwanted gaseous forms from thespillage. It should be understood that each of the above steps/effectsmay act on only a portion of the spilled material, but in preferredembodiments the methods and compositions are delivered and provided in amanner such that one or more of the desired effects is achieved on asubstantial portion, and even more preferably substantially all of thedispersed hazardous material.

In preferred embodiments, the compositions and methods of this inventionare applied from a safe distance, thus allowing substantially all of thespill to be reacted, neutralized, immobilized and/or devolitized (atleast partially but preferentially substantially entirely) with minimalharm to safety workers and others in the area of the spill.

The present inventors have found that the present methods can be carriedout in preferred embodiments by contacting, and preferably substantiallycovering, at least a portion of the hazardous material which has beenspilled, leaked or otherwise the subject of an unwanted dispersal, withone or more binding agents. As a result of the preferred contacting stepof the present invention, a mass is created which comprises thehazardous material and the binding agent in a form that is substantiallyless hazardous than the material without the binding agent. For thepurposes of convenience, but not necessarily by way of limitation, themass comprising the binding agent and the hazardous material issometimes referred to herein as the “treated mass.” The preferredbinding agents can be advantageously used to produce a treated masshaving one or more of the advantageous characteristics, properties,and/or effects described hereinabove. Examples of binding agentsbelieved to be generally adaptable for use in connection with thepresent invention are described in the following pending applications,each of which is assigned to the assignee of the present application:Application No. 60/943026 (Attorney Docket No. H0014675 (33631); andApplication No. 60/943033 (Attorney Docket No. H0012283 (33342)).

In certain preferred embodiments, the binding agent comprises, andpreferably consists essentially of, one or morepolyacrylate-polyacrylamide cross-linked copolymers in accordance withthe teachings contained herein. The preferred cross-linked copolymershave a substantial ability, especially when used in accordance with thepreferred method steps described herein, to achieve and provide atreated mass having the desirable properties, characteristics, effectsand/or modes of operation described herein. For example, the preferredpolyacrylate-polyacrylamide cross-linked copolymers of the presentinvention exhibit a much higher capacity for retaining acidic materials,such as hydrogen fluoride (HF), than many of the other materials whichhave been known for use in such applications. The surprisingly highcapacity of these preferred binding agents is particularly advantageousin accordance with the present methods, compositions and devices. Forexample, the large capacity of the present materials means that therelative proportion of hazardous material (such as HF) to binding agent(e.g., copolymer) in the treated mass is high, which means that theamount of binding material (and potentially the cost thereof) that needsto be transported to the spill site is reduced. This in turn permits thesite, in preferred embodiments, to be treated more quickly and moreeffectively than prior materials, resulting potentially in an importantsaving of health and the environment.

In addition, it has been found by the present inventors that intimatemixtures of polyacrylate-polyacrylamide cross-linked copolymers andacidic materials, particularly hydrogen fluoride, which preferably formas a result of the present methods and the use of the present devices incertain embodiments as disclosed herein, result in a treated mass inwhich the volatility of the hazardous material (such as hydrogenfluoride) is diminished. This treated mass is also preferably moreviscous and has a greater surface tension as compared to the acidicmaterial generally, thus hindering formation of an acidic material in agaseous or fluid state, including an aerosol cloud. Therefore, thecompositions, methods and devices of the present invention permit adramatic reduction in the immediate harm that such a spill wouldotherwise create relative to many of the previously used methods.Moreover, the present invention in certain aspects can make the spillzone easier to clean up and/or remediate.

Accordingly, the present invention in one aspect provides a treatmentmaterial comprising a binding agent, which preferably comprises across-linked copolymer comprising acrylamide and acrylate, preferably inthe form of a solid or a gel, and an agent to assist carrying thecopolymer to the material causing the hazard. In certain preferredembodiments, the carrying agent comprises a propulsion agent, which ispreferably intimately engaged with the copolymer and provides motiveforce to the binding agent to carry it to the hazardous material.Preferably in such embodiments the carrying agent is a gas that isrelatively inert, stable, readily removed or dispersed, and which is notitself inherently harmful to the environment or to health. Examples ofsuch carrying agents include pressurized nitrogen.

In certain highly preferred embodiments of the invention, the presenttreatment material comprises a cross-linked copolymer comprisingacrylamide cross-linked with an acrylic acid salt, wherein suchtreatment material is preferably in the form of a solid or a gel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view, in axial longitudinal section, of oneembodiment of a portable treatment device according to one embodiment ofthe invention.

FIG. 2 is a view of a detail of FIG. 1 on an enlarged scale.

FIG. 3 is a perspective view of another embodiment of a portabletreatment device of the present invention.

FIG. 4 is an environmental view of the treatment device after deploymentat hazard spill.

FIG. 5 is a graphical representation of vapor pressure as a function oftemperature and HF-Gel composition.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The Methods andDevices

Among the method aspects of the present invention, one embodimentincludes the steps of providing a binding agent and applying the bindingagent to at least a portion of the spill or otherwise unwanted dispersalof hazardous material. The binder providing step in certain embodimentscomprises providing a source of the binding agent in its preferred formfor use in treatment. In other embodiments, the binding agent may beprovided in preferred forms as part of applying step. For example, incertain embodiments, the binding agent may be provided in the form of asolid block or sheet of binder which is not well adapted to directapplication to the hazardous material. In such cases, the step ofapplying the binder may include the step of converting the block orsolid sheet into a fine particulate form of the binder. This might occurin certain preferred embodiments, for example, in which an explosive orother high energy force is used to propel the binder material also firstcomminutes the block, film or sheet such that the binding agent isdelivered to the site in the form of fine particles, powder and/oraerosol. Such embodiments may have advantages in certain applicationsrelating to the portability of the material to the hazard site.

In preferred embodiments, the applying step results in contact betweenthe binding agent and the hazardous material that is effective to form atreated mass that is less hazardous than the material prior to thecontacting step. Although it is contemplated that the preferredcontacting step forms a treated mass over a wide range of time periods,it is preferred that the time from initial contact to the point wheresuch less hazardous treated mass is formed is not in excess of severalhours, and more preferably is less than about 3 hours, and even morepreferably less than about 1 hour. This time period will of course be afunction of many parameters associated with each application, and allsuch time periods are within the scope of the present invention.

In certain preferred embodiments, the applying step comprises providinga carrying agent, such as a pressurized gas, and engaging the bindingagent with the carrying agent such that the binding agent is propelled,for example by impulse discharge associated with a pressuredifferential, into contact with the hazardous material. The particularconfiguration of such devices may vary widely within the scope of thepresent invention, and all such configurations are within the scopehereof. It is contemplated, for example, that devices which haveheretofore been used to effect sand blasting or other treatment bycarrying an abrasive or other particulate material to a target site maybe readily adapted for use in connection with the present invention. Itis preferred, however, that the discharge velocity and/or pressure fromsuch devices is controlled, or the impact of the discharge stream isotherwise limited, to ensure or at least minimize the extent to whichthe hazardous material is dispersed over a substantially greater areaupon exposure to the delivery of the binding agent. The use of a net asdescribed in detail hereinafter may serve the purpose, in addition toother purposes, of limiting the impact of the discharge stream to ensureor at least minimize the extent to which the hazardous material isdispersed over a substantially greater area.

In other embodiments, the applying step comprises providing a carryingagent that possesses a motive force produced by a chemical reaction,such as results, for example, from the reaction of an oxidizing agentand a solid fuel subsequent to ignition thereof. In many embodiments,such a carrying agent produced by such a reaction is in the form of anaerosol which carries the binding agent to the hazard site. Such anaerosol is sometimes referred to herein as a “pyrotechnically generatedaerosol.” The binding agent of the present invention can be incorporatedin a canister or module of known type to effect delivery of the bindingagent to the hazardous material. Such embodiments are particularlyeffective under circumstances in which the hazardous material is notexposed to changing environmental conditions, such as large changes inairflow or other weather changes.

In other embodiments, the applying step comprises providing a carryingagent in the form of a fabric or other matrix of fibers which carries orotherwise incorporates or is capable of carrying the binding agent andthen delivering the fabric or other matrix of fibers to the hazardousmaterial. For example, in such embodiments, the copolymer may beembedded in, coated on, and/or integrated in the form of fibers into afabric, such as a web or mesh, which can be readily delivered to thehazardous material, preferably in certain embodiments by forming ablanket or curtain which can be deployed so as to cover or surround atleast a portion of hazardous spill. In certain embodiments, such adeployment may involve forming such a mesh, web, curtain or similararticle and propelling the material containing or carrying the copolymerso as to cover at least a portion of the area of the spill.

Many devices known to those in the art may be used to deliver thebinding agent to the hazardous material, and all such devices are withinthe scope of the present invention. In certain preferred embodiments,the delivery device or system of the present invention includes at leastone container and/or conduit for holding the carrying agent and/or thebinding agent, and means for discharging the carrying agent and thebinding agent from a location safely separated from the hazardousmaterial so as to deliver the binding agent into contact with at least aportion of the hazardous material. In one embodiment, the preferreddevice comprises a fire extinguisher-type device in which at least thecarrying agent is an inert gas stored or otherwise provided underpressure. In other cases, the carrying agent is generated in or by thedevice as a result of an explosive discharge.

One embodiment of a device which utilizes an explosive discharge whichmay be adapted for use in connection with the present invention in viewof the teachings contained herein is illustrated in FIGS. 1 and 2. Withreference initially to FIG. 1, a portable binding agent delivery device,generally indicated 1, comprises a handle 2 and an elongate tubularcasing 3, having a distal end 3 a and a proximal end 3 b which is fixedto the handle 2. A chamber 4 is defined in the casing 3 for housing acharge 5 of a solid substance which can be transformed, at apredetermined temperature, into a carrying agent of the presentinvention, preferably in the form of an aerosol. In one embodiment, thecharge 5 includes not only reactive components but also incorporates abinding agent of the present invention, preferably in small particulateform, distributed therein. The chemical and physical characteristics ofthe reactive components of the mass 5 are not relevant per se for thepurposes of an understanding of the invention and will therefore not bedescribed in detail herein, except to note that they are preferablyselected such that the reaction conditions do not cause a deleteriouschange in the binding agent, that is, a change that would prevent thefunctioning of the binding agent. By way of one example that may beapplicable for certain binding agents, the reactive components comprisea compacted mixture comprising potassium nitrate, a resin, and anorganic oxidizing agent.

A sleeve-like portion 8 of a plug, generally indicated 9, is inserted inthe opening 7.

The plug 9, which is preferably made of plastics material, is held onthe distal end of the tubular casing 3 by means of a peripheral rim 10and by radial interference between the delivery opening 7 and thecentral sleeve-like portion 8. In this portion, a starting capsule,generally indicated 11, is held in an outer or front position, and anassociated delay fuse 12 is held in a position immediately further in orto the rear, interposed between the capsule 11 and the charge 5. Thestarting capsule 11 includes a small inflammable charge 13 arrangedclosely in contact with the end portion 16 a of a manually-operableactivation element 16, for example, a metal wire, a cord, or the like,which the user can pull by gripping a gripping ring 15. The inflammablecharge 13 is contained in a thin inverted cup-shaped container 17, thebase of which has a central hole for the insertion of the cord 14. Theplug 9 has a transverse wall 18 with a hole 19 aligned with the hole inthe container 17. A protective cover 20 closes the distal end of thefire-extinguisher to protect the starting capsule 11 and its activationelement 16. In preferred operation, the user opens the cover 20, gripsthe gripping ring 15 and pulls the cord 14 energetically in thedirection indicated by the arrow A. The friction or other forces exertedby the activation element against the inflammable charge 13 brings aboutignition thereof and the production of a flare which lights the fuse 12.The fuse, which preferably burns for a few seconds, gives the user timeto move his hand away from the distal portion of the device before thecarrying agent and binding agent are discharged. When the combustion,which is propagated along the fuse 12, reaches the reactive elements inmass 5, it triggers the exothermic chemical reaction thereof, with theproduction of an aerosol suspension of particles of extremely smallparticle size. The increase in pressure which accompanies the reactioncauses the expulsion of the plug 9. The aerosol fluid produced by thecombustion of the charge is discharged energetically from the opening 7and can be directed towards the hazardous material from a safe distance.

In an alternative form of the device, the binding agent may be providedas a separate mass positioned to be jettisoned from the end of anelongated version of tubular casing 3. In such embodiments, the cord 14may be passed through a small, sealed opening in a side wall of thecasing, with binding agent located in the tube on the distal side of thecharge 13. In such embodiments, the binding agent may be provided inparticulate form, or the binding agent may be in a form that isfrangible upon operation of the device so as to produce the desired sizeof binding particles. Alternatively, the device of FIGS. 1 and 2 may bemodified to carry a fabric of the present invention packed in a distalportion of the casing so as to be ejected by the reactive forces in amanner designed to cover the desired area in which the hazardousmaterial is located. Further, it should be appreciated that anycombination of any two or more of these options may be incorporated intoa device so, for example, both a binding agent impregnated net and anaerosol of binding agent particles are ejected upon operation of thedevice.

Another embodiment which would permit the multiple modes of operation isdisclosed in FIGS. 3 and 4. Referring now to the drawings, it is seenthat the device preferably incorporates a treatment net of the presentinvention, generally denoted by reference numeral 10. In the preferredembodiment illustrated, the net 12 is generally round in shape and has acentral point 14 and an outer periphery 16. It will be appreciated,however, that other shapes are adaptable for use in accordance with thepresent invention. The net 12 is manufactured from a fabric or meshwhich incorporates a binding agent of the present invention. Forembodiments in which the hazardous material also presents a danger ofexplosion, the net may preferably be formed of an explosion containmentmaterial, which material has a high tensile strength, such as aramidyarn (sold under the trademark KEVLAR and manufactured by the E.I. DuPont de Nemours and Company), which is an organic yarn within the familyof aromatic polyamides.

Although in certain embodiments the net 12 may be un-tethered to thedevice, in certain preferred embodiments the net is connected via atether 40 (see FIG. 4) to the device 10. In the illustrated embodiment,the tether 40 is a tubular tether for purposes of delivering a separateflow of binding agent to the hazardous site as described herein below,although it will be appreciated that the tether need not perform thisfunction in all embodiments. Likewise, it will be appreciated that thenet need not be a carrying agent for binder in those embodiments inwhich the tether 40 is a tubular tether for delivering binding agent tothe hazardous material. Nevertheless, it is generally preferred that thedevice incorporate both mechanisms for delivering binding agent.

In preferred embodiments, a nozzle 18 is located on the net 12 and maybe located at the central point 14. Preferably a series of weights 20are located on the net, preferably about the outer periphery 16 of thenet. The device/system of this embodiment of the invention includes agun 24 having a cone loader 26, appropriate hand grips 28, a butt stock30 (if desired) and a trigger 32. Of course, the shape of the loader maybe readily modified according to the shape of the net being used. Inpreferred embodiments, the gun is configured to have the loader readilyreplaceable so that the shape and size of the net may be selected uponarrival at the site to suit the circumstances of each hazard condition.A bayonet type arrangement may be used to make the loader readilyreplicable to suit size and shape needs. Screw-type mounting of theloader is also possible.

The gun may be pneumatically fired wherein a source of high pressure gas(not illustrated) provides the pneumatic force to fire the gun 24. Thishigh pressure gas source may be either an external or internal canisteror may be a small cartridge that is fed into the gun through the gun'schamber 34. Alternately, the gun 24 may be fired by a firing cartridgesuch as a standard firing blank.

A first tank 36 is provided and holds a carrying agent and/or bindingagent. A second tank is also provided in certain embodiments for holdingcarrying agent and/or binder, or possibly other materials which may bedesirable to deliver also the site of the hazardous material. The firsttank 36 and the second tank 38 are fluid flow connected with the nozzle18 on the net 12 via a conduit 40 which passes through the gun 24 sothat the trigger 32 on the gun can control discharge of the contents ofthe two tanks 36 and 38. In preferred embodiments the two tanks 36 and38 pass through a manifold 42 prior to entering the conduit 40. Asection of the conduit 40 (the section that is disposed between the gun24 and the nozzle 18) may be coiled for compactness of design. Carryingstraps 44 may be provided for ease of carrying of the two tanks 36 and38.

Preferably the manifold 42 is selectable so as to allow the carryingagent to be held in one tank and the binder to be held in another tanksuch that mixing of the two can occur in the manifold or inappropriately designed chambers of the gun. Of course, it is possiblethat in certain embodiments the carrying agent and binder are premixedand held together in one or both of the tanks In other embodiments, thetanks may hold only binding agent and the carrying agent is supplied vianozzles 28.

In operation, the net 12 is folded appropriately and placed into thecone loader 26 of the gun 24 and the gun 24 is appropriately primed(either a firing cartridge is inserted into the firing chamber 32 or asupply of pressurized gas is provided for the gun). Once the useridentifies an appropriate target for treatment, such as a spill of HF,the user squeezes the trigger 32 in order to fire the gun 24 whichpropels the net 12 at the target in order to drape the net 12 over thehazardous material, or at least a portion thereof. The weights 20 alongthe outer periphery of the net 12 help the net land appropriate aboutthe target in order to effectively cover the target area. Continuedsqueezing of the trigger 32 causes operation of the carrying agent suchthat binding agent is discharged through the nozzle 18 onto the targetbeing covered by the net 12. Of course this sequence of operation may bealtered within the scope of the present invention.

In certain embodiments, the deployment means propels the binding agentwith a force adequate to substantially disperse the binding agentthroughout the hazardous liquid. That is, the binding agent is mixedwith the hazardous liquid so as to rapidly and substantially form a lesshazardous composition. In other embodiments, the deployment meanspropels the binding agent onto the surface of the hazardous liquid whereit forms a protective layer over the liquid. In still other embodiments,the deployment means propels the binding agent onto the surface or intoone or more discrete portions of the hazardous liquid from which it issubsequently mixed with the hazardous liquid. It will be appreciatedthat a device or method may comprise any combination of two or more ofthese and other deployment means.

In certain preferred embodiments of the invention, provided is a systemfor suppressing the spread of an acid-containing hazardous material,said system comprising: a container, preferably a portable container,having an interior portion and an exterior side, said interior portionbeing adapted to receive a propellant; a propellant in fluidcommunication with said interior portion; a nozzle, preferably a pivotalnozzle, disposed on said exterior portion and in fluid communicationwith said interior portion; and a binding agent disposed within saidinterior portion or said nozzle. Preferably, the binding agent in suchembodiments comprises at least one cross-linked copolymer comprisingacrylamide units and acrylate units in solid form, preferably pellets,powder, granules, fibers, or some combination thereof. Preferably, thepropellant is disposed within the container and is a combustible fuel, apressurized gas, or a compressed liquid, such as for example, nitrousoxide, carbon dioxide, air, noble gas, hydrofluoroalkane,hydrofluoroolefin, and combinations thereof.

The Compositions

In preferred embodiments, the hazardous material is contacted by acomposition comprising a binding agent, such as an absorbent polymer orcomplexing agent, to form a treated material comprising at least aportion of the hazardous material, wherein the treated material is asolid, semisolid, or viscous liquid, and/or has a vapor pressure that isat or below ambient pressure, and/or has a high surface tension. Inpreferred embodiments, the acidic material, preferably HF, being treatedis substantially unchanged in its chemical make-up from its untreatedstate and, thus, may be readily and quantitatively recovered from thetreated material.

As used herein, the term “restraining” means to hold back or keep incheck.

Examples of restraining include, but are not limited to, immobilizationand suppression of a propensity to volatilize and/or aerosolize.

As used herein, the term “immobilizing” means to impede movement.

As used herein, the term “hazardous” means a property or condition thatimperils or otherwise adversely effects the safety or stability of aperson, plant, animal, or the environment, or is a nuisance ifunrestrained. Examples of hazardous materials include, but are notlimited to, those that are flammable, corrosive, explosive,carcinogenic, toxic, mutagenic, odoriferous, radioactive, volatile, orotherwise chemically unstable.

As used herein, the term “binding agent” means a material having thecapacity to exert or create a strong chemical or physiochemicalattraction between two substances. Examples of strong chemical andphysiochemical attractions include ionic bonding, nonionic bonding,electrophilicity, electrophobicity, and the like. Examples of bindingagents include, but are not limited to, absorbent polymers, such ashydrogels, and complexing agents, such as ionic liquids.

Preferably, the binding agent is in a form that is easily and rapidlydeployable into a liquid or onto the liquid's surface. Examples ofeasily and rapidly deployable forms include liquid and solids such aspowder, granules, pellets, fibers, or combinations thereof.

In certain preferred embodiments, the composition binds the hazardousmaterial in such a way as to readily release the hazardous materialunder certain conditions, such as changing the temperature and/orpressure of the composition. In such embodiments, the hazardous materialmay be recovered after it has been re-secured.

In certain embodiments, the carrying agent may comprise a compressedgas, such as air, nitrogen, carbon dioxide, or a noble gas instead of,or in addition to, an oxidizable fuel. For such embodiments, thecompressed gas is rapidly released and propels the binding agent.

The choice of binding agent is primarily determined based upon thehazardous material held in the receptacle. Examples of hazardousmaterials that may be practiced with the present invention include, butare not limited to, nitric acid, concentrated sulphuric acid,concentrated hydrochloric acid, aqueous sodium cyanide, anhydrous sodiumcyanide, aqueous hydrogen cyanide, anhydrous hydrogen cyanide, bromine,bromine trifluoride, ammonia, trifluorophosphine, titaniumtetrachloride, oleum, chlorosulphonic acid, chlorine, fluorine, aqueoushydrogen fluoride, anhydrous hydrogen fluoride, phosgene, petroleum, andderivatives thereof. As used herein, the term “derivative” means acompound or chemical structure having the same fundamental structure,underlying chemical basis, or chemical properties as the relevantrelated compound. Such derivatives are not limited to, but may include,a compound or chemical structure produced or obtained from the relevantrelated compound.

In certain preferred embodiments, the binding agent is an absorbentmaterial.

Particularly preferred absorbent materials are absorbent polymers.Examples of absorbent polymers include, but are not limited to,polyacrylamide, polyalkylacrylamide, polyacrylate, polyalkylacrylate,polyacrylic acid salts, cross-linked polyacrylamide-polyacrylatecopolymer, cellulose ethers, modified starches, starch derivatives,natural gum derivatives, ethylene oxide polymer, polyethyleneiminepolymer, polyvinyl pyrrolidone polymer, and mixtures or copolymersthereof. Such binders are described, for example, in U.S. Pat. No.4,383,868 and U.S.Pat. No. 6,177,058, each of which are incorporatedherein by reference.

These absorbent polymers are particularly preferred for binding nitricacid, concentrated sulphuric acid, concentrated hydrochloric acidsolution, aqueous sodium cyanide solution, bromine, titaniumtetrachloride, oleum, chlorosulphonic acid and anhydrous hydrogenfluoride.

For binding anhydrous and aqueous hydrogen fluoride,polyacrylate-polyacrylamide cross-linked copolymers, particularly thosederived from a polyacrylic acid salts, and mixtures of cross-linkedpolyacrylamide-polyacrylate copolymer and at least one ofpolyacrylamide, polyalkylacrylamide, polyacrylate, polyalkylacrylate,and polyacrylic acid salts.

In certain embodiments, the binding agent is a complexing agent.Preferred complexing agents include, but are not limited to, organicsalts, particularly organic salts that form ionic liquids. Examples ofpreferred organic salts include, but are not limited to, salt comprisinga cation selected from the group consisting tetraalkylphosphonium,tetraalkylammonium, pyridinium, N-alkylpyridinium,N,N′-dialkylimidazolium, and imidazolium. Particularly preferred organicsalts is a substituted imidazolium chloride, with1-methyl-3-ethylimidazolium chloride being more preferred. These organicsalts are particularly useful for binding chlorine. Preferredcompositions of these organic salts and chlorine have a vapor pressurethat is lower than the ambient vapor pressure.

Other binding agents that may be practiced with the invention includepolyacrylic acid which is useful for binding aqueous and anhydroushydrogen cyanide and ammonia; calcium stearate which is useful forbinding petroleum and petroleum-based compounds; and azoliumtetrafluoroborate, which is useful in producing an electrolyte withbromine trifluoride and trifluorophosphine.

In certain preferred embodiments of the invention the binding agentcomprises, and preferably comprises in major proportion and even morepreferably consists essentially of at least onepolyacrylate/polyacrylamide crossed-linked copolymer. As used herein,the term “copolymer” means a polymer having two or more differentmonomer residues that have been polymerized and constructed as one ormore chains. The arrangements of these monomer units in the chaininclude those that regularly alternate the different monomers or thosethat repeat monomer units in regular or random sequences. In addition,the chain can be straight, branched, or grafted, or can exist as a blockcopolymer.

As used herein, the term “cross-linked” means the attachment of twochains of polymer molecules by bridges composed of an element, afunctional group, a compound, or a polymer unit, which join certainatoms of the chains by primary chemical bonds. In certain embodiments,cross-linking occurs between two or more polymer chains to form acopolymer structure. In certain other embodiments, cross-linking occursbetween two or more copolymer chains that are similar in arrangement.Preferably, cross-linking occurs between amide groups and carboxylicgroups of the copolymer.

The cross-linked copolymer of the present invention in its dry form ispreferably solid in the form of a powder, granules, pellets, and thelike. When exposed to acidic material, particularly hydrogen fluoride,the copolymer chains expand or unfold and uptake or absorb the acidicmaterial to form a solid or a semi-solid material, such a gel. Due tothe copolymer's cross-linking, the copolymer is preferably insoluble inthe acidic material, particularly hydrogen fluoride, and water.

Though not intending to be bound by a particular theory, it is believedthat hydrogen fluoride uptake by the copolymer is facilitated by thenegative carboxylic groups of the copolymer and their hydration withhydrogen fluoride molecules. For embodiments in which the copolymercomprises an alkali metal or ammonium ion (e.g., copolymers form with anacrylic acid salt), it is believed that, in the presence of hydrogenfluoride, the alkali metal or ammonium disassociates from the carbonylgroup creating two ions: a carboxyl (COO⁻) and an alkali metal orammonium ion (e.g., Na⁺). The carboxyl groups begin to repel each otherbecause they have the same negative charge. This repulsion unfolds orswells the polymer chain. The swelling action also allows more hydrogenfluoride to associate with the polymer chain and reside in the spaceswithin the polymer's network.

The cross-linking between polymer chains prevents the copolymer fromdissolving in liquid hydrogen fluoride or other liquids. When the chainsbecome hydrated, the cross links prevent them from moving aroundrandomly. In general, the cross-linking affects the copolymer'sadsorption capacity, with more cross links in a chain corresponding to adecrease in the polymer's ability to adsorb liquids. (See, e.g., Osmosisand Super Absorbent Polymers, U. of Illinois at Urbana-Champaign.)However, the inventors have surprisingly found that cross-linkedcopolymers of the present invention have a significantly higher capacityfor liquid hydrogen fluoride compared to the copolymer's constituentpolymers individually.

Preferred cross-linked copolymers of the present invention areconstructed of both acrylamide units and acrylate units. Within thescope of the term “acrylamide”, included is acrylamide itself (i.e.,2-propenamide), polyacrylamides, polyalkylacrylamides (e.g.,polymethylacrylamide), monomer residues of such acrylamides, andderivatives thereof. As used herein, the term “derivative” means acompound or chemical structure having the same fundamental structure orunderlying chemical basis as the relevant related compound. Such aderivative is not limited to a compound or chemical structure producedor obtained from the relevant related compound. Acrylamide units thatcan be utilized in the present invention include individual structuralunits of acrylamide, repeating units of acrylamide, and polymer chainsconstructed, at least in part, of acrylamides.

Within the scope of the term “acrylate”, included is acrylic acid (i.e.,2-propenoic acid), acrylic acid salt (e.g., sodium acrylate, potassiumacrylate, and the like), alkylacrylates (e.g. methyl acrylate, butylmethylacrylate, and the like), polyacrylates, polyalkylacrylates,polyacrylic salts, monomer residues of such acrylates, and derivativesthereof. Acrylate units that can be utilized in the present inventioninclude individual structural units of acrylates, repeating units ofacrylates, and polymer chains constructed, at least in part, ofacrylates.

Particularly preferred acrylic acid salts include potassium acrylate,sodium acrylate, and ammonium acrylate, with potassium acrylate beingparticularly preferred.

Polyacrylate-polyacrylamide cross-linked copolymers are commerciallyavailable from a variety of sources including Degussa AG of Krefeld,Germany (sold under the trade name STOCKOSORB®), Kyoritsu YukikogyoKenkyusho of Japan (sold under the trade name Hymosab®200), and Aldrichof Milwaukee, Wisconsin (Cat. No. 43,277-6).

Copolymers of the present invention preferably comprise from about 1 toabout 99 weight percent, and more preferably from about 5 to about 60weight percent, of acrylamide units based upon the total weight of thecopolymer. Copolymers of the present invention also preferably comprisefrom about 1 to about 99 weight percent, and more preferably from about5 to about 60 weight percent, of acrylate units based upon the totalweight of the copolymer.

Generally, the cross-linked copolymers used in the invention havemolecular weights of from about 5,000 to about 10,000,000. Preferably,cross-linked copolymers with molecular weights of from about 5,000 toabout 5,000,000 are used.

The inventors have found that the cross-linked copolymers of the presentinvention have an exceptionally high capacity for hydrogen fluoride. Itis possible to measure the capacity of a polymer for HF by mixing thepolymer with an excess of HF, allowing the mixture to sit for a periodof time such that the polymer becomes saturated, filtering off theexcess HF, and weighing the saturated polymer as well as the excess HF.

Although cross-linked copolymer capacity is important to a practicalHF-gel system, other properties should be considered as well. Otherproperties of interest include exotherm upon mixing the copolymer andHF, vapor pressure of the resulting composition, viscosity of thecomposition, gelatinization time, density/volume of the startingpolymer, capacity of the composition under pressure, ease of recovery ofthe HF from the composition, reduction in HF aerosol formation by thesystem, and mixing or dispersing of the polymer into HF.

It is contemplated therefore, that in addition topolyacrylate/polyacrylamide crossed-linked copolymers, otherHF-absorbing polymers and copolymers may be practiced with the presentinvention. Preferably, these other polymers and copolymers will be mixedwith the polyacrylate/polyacrylamide crossed-linked copolymer tooptimize several properties of the composition. For example, forapplications in which the time required to gel a given quantity of HF isimportant, the invention involves a mixture a copolymer having high HFcapacity and another polymer or copolymer which gels quickly. Theevolution of excessive heat may accompany the formation of the gel whenHF and a copolymer or polymer are mixed. Accordingly, certainembodiments of the invention utilize a mixture of a high capacitycross-linked copolymer and a polymer or copolymer with a lower capacitythat exhibits a smaller exotherm.

Examples of other polymers that may be mixed with apolyacrylate/polyacrylamide crossed-linked copolymer include thosedescribed in U.S.Pat. No. 6,177,058, which is incorporated herein byreference. Preferred polymers include water soluble polymers selectedfrom the group consisting of cellulose ethers, modified starches, starchderivatives, natural gum derivatives, polyacrylic acid salts, ethyleneoxide polymer, methacrylic acid polymer, polyethyleneimine polymer,polyvinyl pyrrolidone polymer and mixtures thereof

Without departing from the scope of the invention, it will be recognizedthat other components also may be included in the binder compositions ofthis invention. The specific nature of these components will depend onthe desired end use of the compositions.

Preferably hydrogen fluoride may be recovered readily from the treatedmaterial by exposing the treated material to conditions effective toliberate hydrogen fluoride vapors. One means of liberating hydrogenfluoride vapor is by heating the composition at elevated temperatures,generally from about 0 to about 200° C., preferably from about 80 toabout 150° C., resulting in the liberation of hydrogen fluoride vapor.The vapor may then be condensed by any convenient means. Alternatively,the hydrogen fluoride may be liberated by decreasing the pressure overthe composition or increasing both the pressure and temperature and thencondensing the vapors. This alternative means for recovering hydrogenfluoride may be accomplished at pressures of from about 60 to about 1psia and temperatures of from about 20 to about 50° C. As yet anotheralternative, hydrogen fluoride value may be recovered from the treatedcompositions by use of the compositions in any of the wide variety ofprocesses that use hydrogen fluoride.

EXAMPLES

The invention will be clarified further by a consideration of thefollowing examples that are intended to be purely exemplary.

Example 1

Approximately, 0.5 grams of Stockosorb M (acrylamide/potassium acrylatecopolymer, cross-linked), commercially available from Degussa AG, ofKrefeld, Germany, was placed into a perfluoroalkoxy (PFA) vessel fittedwith a screen above the polymer, and evacuated. The PFA vessel was thenweighed, and cooled to about −78° C. About 29 grams of anhydrous HF weredistilled onto the polymer. The PFA vessel was warmed to roomtemperature and weighed. After about two hours, the PFA vessel wasinverted and the excess HF drained into a second, evacuated PFA vessel.The HF-polymer gel remained on the filter screen in the first PFAvessel. The vessel containing the polymer gel was again weighed and thepolymer found to have absorbed about 45.6 grams of HF per gram ofpolymer. This experiment was repeated several times and the averagecapacity was found to be about 45.2 grams of anhydrous HF per gram ofpolymer, which is reported in Table 1.

Examples 2-4

The procedure in Example 1 was repeated for Examples 2-4, except thatStockosorb

M was substituted for Stockosorb CW, FW, and SW, respectively. Theresults for each composition are reported in Table 1.

Example 5

The procedure in example 1 was hard to perform with small particle sizedpolymers and had unacceptable scatter in the results, so a differentapproach was taken to characterize their capacity. Approximately 0.5grams of Stockosorb CW was placed in a PFA vessel, connected to a vesselcontaining HF, and the system was evacuated. The valve of the HFcontainer was opened and the polymer allowed to absorb HF vapor for twodays. At the end of this period the polymer had adsorbed 37.62 grams ofHF/gram of polymer. The experiment was repeated with fresh polymer whichwas allowed to absorb HF vapor for about 4 days. At the end of thisperiod the polymer had adsorbed 40.90 grams of anhydrous HF per gram ofpolymer. The average of these two measurements is reported in Table 1.Although this technique is different than the approach described inexample 1, it shows the polymer absorbs much more HF than previouslyreported systems.

Example 6

The procedure in example 2 was repeated with Stockosorb FW. The averageof multiple runs for each composition is reported in Table 1.

Comparative Examples 7-15

The procedure in example 1 was repeated, except with the polymers listedTable 1. The HF capacities of these polymers is summarized in Table 1.The test results show that acrylamide/potassium acrylate cross-linkedcopolymers have a much higher HF capacity compared to acrylate polymers.

Example 16

A small amount of Stockosorb M was placed into a previously weighed FEPvessel. The vessel was evacuated and weighed again to determine theweight of polymer (0.1111 grams). The sample was then reconnected to themetal vacuum line, cooled to −78 ° C. and an excess of HF distilled ontothe polymer. The weight of the vessel+polymer+HF was then obtained. Thevapor pressure of this system was measured at 20 ° C. A small amount ofHF was then distilled from the vessel and the weight of thevessel+polymer+HF was then obtained. The vapor pressure of this reducedHF system was again measured at 20 ° C. This procedure was repeatedmultiple times until nearly all of the HF had been removed. Thisexperiment was run in triplicate, the vapor pressures were thencalculated at several standard compositions and plotted in FIG. 1. Theresults demonstrate the low vapor pressure of the composition.

Example 17

Example 16 was repeated at 0° C. The results are shown in FIG. 1.

Example 18

Example 16 was repeated at 40° C. The results are shown in FIG. 1.

Example 19

Example 16 was repeated at 60° C. The results are shown in FIG. 1.

Example 20

About 8 grams of Stockosorb M was quickly added to a cylinder containingabout 180 grams of HF at 20° C. In about 160 seconds the HF was about65% gelled based on the height of the expanding polymer in the cylinder.Shortly afterward, the HF was completely gelled. The temperature of thecylinder contents reached 29° C. before cooling to 20° C. This testdemonstrates the rapid uptake of HF by the copolymer.

Example 21

Approximately, 0.49 grams of Stockosorb M (acrylamide/potassium acrylatecopolymer, cross-linked), commercially available from Degussa AG, ofKrefeld, Germany, was placed into a perfluoroalkoxy (PFA) vessel fittedwith a screen above the polymer, and evacuated. About 78.8 grams ofaqueous HF (49 wt %) transferred onto the polymer. The PFA vessel wasweighed. After about two hours, the PFA vessel was inverted and theexcess HF drained into a second, evacuated PFA vessel. The HF-polymergel remained on the filter screen in the first PFA vessel. The vesselcontaining the polymer gel was again weighed and the polymer found tohave absorbed about 72.5 grams of aqueous HF per gram of polymer.

Comparative Example 22

About 150 grams of water was added to 0.5 grams of Stockosorb M andallowed to sit for about 2 hours. The mixture was then filtered. Basedon the weight increase, the polymer absorbed about 254 grams of waterper gram of polymer.

Comparative Example 23

About 165 grams of deionized water was added to 0.58 grams ofpoly(acrylic acid) partial sodium salt from Aldrich, mixed, and filteredas in comparative example 14. The polymer absorbed about 231 grams ofwater per gram of polymer. The Stockabsorb M therefore absorbed about10% more water than this Aldrich polymer. Based on these water examplesthe two polymers have very similar absorbent capacities for water. It istherefore completely unexpected that the Stockosorb absorbs about 22times more HF than the Aldrich polymer (Table 1).

Example 24

Polymer A, which quickly absorbs HF will be mixed with polymer B whichabsorbs HF more slowly, but yields a gel with a lower vapor pressurethan polymer A. This polymer mixture will then be added to HF. Theresulting gel will form quickly and will have an acceptably lower vaporpressure and reduced tendency to form HF aerosol droplets.

Example 25

Polymer C, which quickly absorbs HF, will be mixed with polymer D whichabsorbs

HF more slowly, but has a higher capacity for absorbing HF. This polymermixture will then be added to HF. The resulting gel will form quicklyand will have an acceptably high capacity for HF.

Example 26

Polymer A, B, and D will be mixed and then added to HF. The resultinggel will form quickly, will have a good capacity for absorbing HF, anacceptably low vapor pressure, and a reduced tendency to form HF aerosoldroplets.

TABLE 1 Polymer Capacity (grams HF/gram polymer) Avg. Value Ex. Avg.(vapor No. Value expt)  1 Stockosorb ® M (polyacrylate-polyacrylamide45.20 cross-linked copolymer) 2/5 Stockosorb ® CW(polyacrylate-polyacrylamide 52.72 39.26 cross-linked copolymer) 3/6Stockosorb ® FW (polyacrylate-polyacrylamide 75.42 27.14 cross-linkedcopolymer)  4 Stockosorb ® SW (polyacrylate-polyacrylamide 57.56cross-linked copolymer)  7 AQUAKEEP ® (sodium polyacrylate) 3.50  8Luquasorb ® 1030 (sodium polyacrylate) 2.50  9 Luquasorb ® 1270(potassium polyacrylate) 1.70 10 Luquasorb ® 1210 (sodium polyacrylate)2.30 11 AP73 (cross-linked sodium polyacrylate) 1.50 12 Aldrich ® Na⁺salt (sodium polyacrylate) 1.90 13 Aldrich ® K⁺ salt (potassiumpolyacrylate) 1.92 14 AP80HS (sodium polyacrylate) 2.52 15 SXM 70 (saltof polyacrylic acid) 1.83

Example 27

An empty dry chemical-type fire extinguisher canister equipped with anozzle and a triggering mechanism will be provided. The canister will bepartially filled with binder comprising a cross-linked copolymercomprising acrylamide units and acrylate units. The canister will thenbe pressurized using a compressed gas.

Liquid hydrogen fluoride will be poured into shallow pan. The nozzle ofthe canister will be directed to the hydrogen fluoride and thetriggering mechanism activated. The binder will then be released fromthe canister and propelled into contact with the hydrogen fluoride.

Upon contacting the hydrogen fluoride, the binder will start to form agelatinous material comprising the copolymer and the hydrogen fluoride.Within minutes, substantially all of the hydrogen fluoride will beimmobilized within the gelatinous material.

Having thus described a few particular embodiments of the invention, itwill be apparent to those skilled in the art, in view of the teachingscontained herein, that various alterations, modifications, andimprovements not specifically described are available and within thescope of the present invention. Such alterations, modifications, andimprovements, as are made obvious by this disclosure, are intended to bepart of this description though not expressly stated herein, and areintended to be within the spirit and scope of the invention.Accordingly, the foregoing description is by way of example only, andnot limiting. The invention is limited only as defined in the followingclaims and equivalents thereto.

1. A composition for treating hazardous material containing acidicmaterial comprising a binding agent and a carrying agent for deliveringsaid binding agent to the hazardous material, said binding agentcomprising at least one cross-linked copolymer comprising acrylamideunits and acrylate units.
 2. The composition of claim 1 wherein saidcomposition further comprises a water soluble polymer selected from thegroup consisting of cellulose ethers, modified starches, starchderivatives, natural gum derivatives, polyacrylic acid salts, ethyleneoxide polymer, methacrylic acid polymer, polyethyleneimine polymer,polyvinyl pyrrolidone polymer and mixtures thereof.
 3. A system capableof treating acid-containing hazardous material, said system comprising:binding agent; carrying agent for carrying said binding agent to thearea of the hazardous material, said carrying agent comprising a fabriccarrying or made from said binding agent; a discharge chute capable ofholding said fabric; and means for propelling said fabric to the site ofthe hazardous material from a safe distance therefrom such that thefabric comes in contact with at least a portion of said hazardousmaterial and wherein said binding agent reduces the risk from saidhazardous material.
 4. The system of claim 3 wherein said dischargechute is connected to a gun which carries said propelling means.
 5. Thesystem of claim 3 wherein said system further comprises at least a firsttank containing at least a portion of said binding agent and means topropelling binding agent from said tank to the site of the hazardousmaterial from a safe distance therefrom.
 6. A system capable of treatingacid-containing hazardous material, said system comprising binding agentand means for delivering said binding agent to the area of the hazardousmaterial, said binding agent comprising a cross-linked copolymercomprising acrylamide units and acrylate units, wherein said systemfurther comprises at least a first tank containing at least a portion ofsaid binding agent and means to propelling binding agent from said tankto the site of the hazardous material from a safe distance therefrom.